package helper
{
   public class Singleton {
      private static var _instance:Singleton;               
 		
      public function Singleton(sE:SingletonEnforcer) {}               
 
      public static function getInstance():Singleton {
         if(_instance == null) {
            _instance = new Singleton(new SingletonEnforcer());
         }
         return _instance;
      }               
 
      public function sayHello():void {
         trace("Hello World!");
      }
   }
}     
class SingletonEnforcer {}